Posted
by
Soulskillon Thursday June 28, 2012 @10:09AM
from the nice-work-scoob dept.

scibri writes "A few weeks ago, reports of a mysterious spike in carbon-14 levels in Japanese tree rings corresponding to the year 775 intrigued astronomers. Such a spike could only have been caused by a massive supernova or solar flare, but there was no evidence of either of these at that time. Until Jonathon Allen, a biochem undergrad at UC Santa Cruz, Googled it. He found a reference in the Anglo-Saxon Chronicle to a 'red crucifix' appearing in the sky in 774, and speculates that it could have been a supernova hidden behind a cloud of dust, which could mask the remnants of the exploded star from astronomers today."

A.D. 774. This year the Northumbrians banished their king,
Alred, from York at Easter-tide; and chose Ethelred, the son of
Mull, for their lord, who reigned four winters. This year also
appeared in the heavens a red crucifix, after sunset; the
Mercians and the men of Kent fought at Otford; and wonderful
serpents were seen in the land of the South-Saxons.

I'm a little dubious that a supernova, even one visible only in the west after sunset, would be described as a red crucifix. In astronomical photos stars look like crosses, but that's an artifact of the telescope optics, which they didn't have in the dark ages. A supernova just wouldn't look like a cross.

On the other hand, I doubt it's aurora. Since England is pretty far north, and they didn't have artificial lights at night, they would see aurora far more often than we do now, and it just wouldn't rate

As far back as 1870, he says, John Jeremiah published an article in Nature that referred to the same wording from the Anglo-Saxon Chronicle. Jeremiah proposed then that it might have been an early description of the Northern Lights2.

"Another possible explanation could be an ice-crystal display," adds Olson, noting that the red "crucifix" could have been formed by sunset light illuminating high-altitude ice particles in both vertical and horizontal bands of light.

But, it could also have been a previously unrecognized supernova. Plenty of supernovae now known to astronomers "are simply missing" in the historical record, says Gyuk. "The sky is a large place and the historical record is not very good."

Since I can't mod you +6... what blows my mind is this was the only informative comment by JustOK that I could quickly find. Most are just +5 Funny.

This is one of the few remaining reasons I visit slashdot - the rare insightful comment, and the inevitable up-moderation it gets. And of course the meta-hive-mind, where someone much like yourself makes a connection. In a way, it's the closest I can get to James Burke's Connections article in Scientific American.

(By the way... getting that umlaut right reminds me that Slashdot is still in the Web stone age... they don't even support UTF-8 yet. Evidence seems to indicate that the server-side code for Slashdot is Perl! Good Grid, how backwoods can a web developer get?)

(Yet another note: I just had an interesting episode with builtwith.com, and they say the HTML on Slashdot is

You're simply not going to get a definitive record of a celestial event in 8th century Europe. Records are very scanty, often non-existent. This is so marked that it's led to an entertaining conspiracy theory [wikipedia.org] or two [wikipedia.org] claiming that the early Middle Ages didn't actually exist and were faked at some later date. Back in the real world, there's so little evidence for most things about Anglo-Saxon England that the claim that the people of York chose Ethelred, son of Mull to be their king is almost as suspect as the claim about the wonderful serpents.

So the best you can usually hope for in the English 8th century is a monk somewhere recording events in the Anglo-Saxon Chronicle (or a Anglo-Saxon Chronicle -- there were a few of them made at different times and in different places). The Chronicle doesn't really go for detail. They sum up a year in a few declarative sentences, with no description, so you're never going to get a description of a celestial event, you're going to get a simplfied interpretation of it. This interpretation will be in terms that the monk or the eyewitnesses he got his information from understood. They didn't know anything about supernovas, but he knew about miraculous crosses in the sky, like that which appeared to the future Roman Emperor Constantine during his fighting against his rival Maxentius. So whatever it was that someone saw, it got interpreted as a crucifix.

The point isn't that something definitely appeared in the sky in 774. There's a chance that someone made up the red crucifx, or hallucinated it, or the chronicler lied or garbled a story he heard fifth-hand. But if it did happen, there's no reason to think that there will be better written evidence than a vague line in one copy of the Anglo-Saxon Chronicle.

When you're talking about events 1200 years ago you're not exactly looking for a telescope picture.

There's evidence of a supernova, or possibly something else, from that time period in Japan. So what was it? Well, apparently in the UK they observed some weird shit that could have been a supernova. So it might actually have been a supernova.

Imagine if this was the other way. There was some written european evidence of some weird red thing in the sky in 774. What would tell what that red thing was? a spike in carbon 14 in tree rings from that time period would make 'supernova' a good guess.

It's not really a sciences problem, it's a language problem. Outside of Japan I bet most people didn't really care, and the Japanese didn't have the desire to search through piles of old foreign language documents on the vague guess they might say something that could have caused a carbon 14 spike in 773, 774 or 775. Digitized images and electronic search make that problem easier, and now the question for verification becomes one of finding if there are similar descriptions in other languages for that time period.

If other references are found that can indicate a better location, shouldn't there be a possibility of still finding the remnants today using one of the new sets of instruments available? I'm assuming without better information (date, approximate location in the sky) it'd be more like searching for a needle in a freshly mown hayfield, but even given the current information, it should be able to restrict the search to a single band across the sky.

I'd consider it credible of -some- event (where said event could range from the consumption of mushrooms to an actual celestial event). Any supporting material (eg: petroglyphs by pre-writing peoples) would be extremely helpful, but ancient sites are not always well-recorded and are frequently poorly-preserved, making that kind of data hard to find.

A supernova? Maybe, but I still see nothing in the evidence to suggest that it was specifically that. I would imagine a GRB within a narrow range of distances co

Now this undergrad needs to get funding to track the source article down in it's original form and have it authenticated and cross verified with other ancient works. He will also need several other undergrads to cross check his work, several hours of super computer time or better their own workstations, also the usual funding for a trip (I mean "conference") of three weeks in the Bahamas to discuss all this with his peers after he writes the paper up and has it submitted to the proper journals to have the proper peer review that noone can afford to read in the correct publications. I figure 2 to 3 million dollars should do it. After all this could be the tiny spark of evidence as why reading tree rings and it's tree ring data should not or should be included in figuring out how Global Warming going back then and now, and how the whole normalizing of the tree ring data should be rethought! Micheal Mann should be all over this!

This is why I work in Information Technology with a History degree. When a primary source in 774 is a reference to a colored spot in the sky, you might as well include that they rode on unicorns that vomited rainbows.

Always remember Betteridge's Law of Headlines [wikipedia.org] whenever you see a question mark at the end of a headline like this. Question headlines have always been a trademark of poor article writing.

Ending a headline in a question mark merely means they're writing in a language that is younger than Latin and has borrowed the shorthand notation developed by barbarians unwilling to write the questions out in full.

Well, for it to have affected the entire planet, the supernova would have had to be on the celestial equator. If it was displaced significantly from the celestial equator, then the radiant energy from the supernova simply wouldn't hit the Earth's surface at certain latitudes - for the same reasons that the polar regions experience periods of perpetual darkness.

It's irrelevant because C14 is derived from N14 in the upper atmosphere, and the atmosphere is well-stirred. The higher C14 would get mixed in globally no matter which side of the Earth was irradiated.

The real issue is that all these sorts of "global event in year X" events start with a discovery at one or a few sites. For example, the iridium spike at the Cretaceous/Tertiary boundary was first found at Gubbio, Italy. Then it was found at dozens of other sites world-wide at the same boundary, but it took

It's irrelevant because C14 is derived from N14 in the upper atmosphere, and the atmosphere is well-stirred. The higher C14 would get mixed in globally no matter which side of the Earth was irradiated.

Actually, only the troposphere is well stirred. The stratosphere and layers above it aren't stirred as much, and they settle into layers: hence stratosphere. Nevertheless, your point is well taken. By the time the excess C14 reaches the leaves of the trees, it is most likely well dispersed all over the planet.

Maybe it has something to do with Japan being an island and having certain tree types. It was atmospheric carbon-14 which means it got down into the trees and maybe that only happens in certain weather and airflow patterns or something. Still, you would think it'd hit more of the Earth anyway like Hawaii or something but the article doesn't seem to indicate that.

Nobody said that the wood that had the carbon 14 spikes was in trees still alive today nor that only Japanese trees show the spike, just that wood that has been reliably dated to 775 in japan has the spike.

Oh, I just realized not a lot of trees live to be 1300 years old. So...there's that, lol. Someone take a geiger counter to the redwood forests:-P

No, we will have to chop them all down to correctly analyze the rings. Of course, in order not to waste the wood we will sell it to the highest bidder. And we will have to cut down a large number of trees so as to get a good statistical sample.

In those days, the earth was still stationary at the centre of the universe. Under those conditions astronomical phenomena may have only been visible from and effect some parts of the earth and not others. I guess it would depend on which crystal sphere the supernova occurred in.

The way it sounds to me: kid sees post on Slashdot. Kid "reports his findings" to some prof. Kid gets published for doing even less than a Google search, he just stole* the information from a/. post. *Stolen because he lied about how he got the information.

"The increase in 14C levels is so clear that the scientists, led by Fusa Miyake, a cosmic-ray physicist from Nagoya University in Japan, conclude that the atmospheric level of 14C must have jumped by 1.2% over the course of no longer than a year, about 20 times more than the normal rate of variation"

Does this mean that new supernova contributed 1.2% of radiation of all stars, including Sun? Does Sun contribute to Carbon 14 contents in tree rings?

Were similar tree ring changes has been detected during known supernova events in history?

I didn't get way into physics in high school but I was interested. Hearing this explanation confuses me so there are probably more people than me who are wondering this. How exactly can cosmics radiation can cause carbon atoms in the atmosphere to gain neutrons? No new carbon is being formed, obviously, so existing carbon atoms would have to be turning into carbon-14 and I didn't think it was possible to just slip in another neutrons without basically blowing up the nucleus of any atom. I mean we don't "make" tritium for example by stuffing in more nuetrons magically, we have to sort it out of seawater. I would bet I could randomly throw my mouse and hit 3 physicists here at slashdot so could someone explain what the correlation between supernovas and carbon 14 is?

If you'd bothered to wikipede: "Cosmic rays are energetic charged subatomic particles, originating in outer space.They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation." http://en.wikipedia.org/wiki/Cosmic_rays"Carbon-14 is produced in the upper layers of the troposphere and the stratosphere by thermal neutrons absorbed by nitrogen atoms. When cosmic rays enter the atmosphere, they underg

It's only a few nuclei that fall completely apart when they encounter a neutron. In fact, the first time physicists observed that happening, it was so unexpected that they didn't realize at first that it was what they were seeing.

Most absorb the neutron, often having a secondary reaction that changes them to a different element.

Tritium is not sorted out of seawater. With a half-life of 12 years it isn't found in nature. You may be thinking of deuterium.

The reason Carbon 14 dating works is because cosmic rays hitting the atmosphere keep creating more Carbon 14, keeping the level of Carbon 14 in the atmosphere constant fairly constant. Carbon 14 is absorbed through photosynthesis, resulting in the amount within a plant being roughly the same proportion as the amount in the atmosphere. Once the plant dies (or in the case of tree rings, once that ring is done growing) no more Carbon 14 is absorbed, and the amount in the plant material starts to decline alon

"A.D. 793. This year came dreadful fore-warnings over the land of the Northumbrians, terrifying the people most woefully: these were immense sheets of light rushing through the air, and whirlwinds, and fiery, dragons flying across the firmament. These tremendous tokens were soon followed by a great famine: and not long after, on the sixth day before the ides of January in the same year, the harrowing inroads of heathen men made lamentable havoc in the church of God in Holy-

The 775 C-14 spike is 20 times the normal level. According to this paper the closest recent supernova (the Crab Nebula supernova in 1054) was only capable of producing a spike 8% more than normal.

To get a 2000% increase over normal you need a supernova 16 times closer, about 400 light years away, and 250 times brighter than 1054. The angular diameter of such a remnant today would be larger than the full moon, it seems unlikely that there are any dense dust clouds of this visible size for an object like this to hide behind. An obscure reference in the Anglo Saxon Chronicle does no a credible supernova make.

Centuries later, scientists figure out what actually happened using careful observation. Number of times this has happened: too many to count.

And most of these "observations" of weird stuff in the night sky were due to the aurorae. Even in modern light-polluted England where the telly rules the evenings, some people will always spot a decent aurora. Here are examples from England [nationalgeographic.com] and Scotland [bbcimg.co.uk], which are nothing compared to those visible at higher geomagnetic latitudes.

They drank more alcohol back then than in modern times. Before water treatment facilities, you drank the beer which was sterilized during the boiling, the alcohol would kill wild bacteria, and the hops inhibited growth of other bacteria. Beer is also a way to keep grains stored for a longer period of time; dry grain does eventually spoil.

Turns out it wasn't a religious text (didn't notice that till after I commented). The "red crucifix" is a somewhat religious snippet, though, even if the text itself was primarily a historical chronicle.

You seem to have a problem with cause-effect relationships. The monks were the only chroniclers because the church held a monopoly on education. Probably, without the church's monopoly, there would have been non-religious chroniclers who would have reported the facts without religious interpretations.

Hmmm given all the evidence, I'd say it's actually a 49% chance red crucifix = UFO explosion over Japan (since apparently the radiation-stuffed trees were localized to just Japan I guess, although not many trees elsewhere live to be 1300 years old) and 49% chance there's an obvious link between reactor meltdown and the year 775 via a magic quantum portal time teleportation particle traveling effect thing that blasted carbon-14 into the past and 2% chance that we're all living in a computer simulation and so

There was no year zero. Due to various historical "stuff" the year just before "year 1 after Christ" is "year 1 before Christ". Blame the Romans. The Christ from the mythology was born in "the year 1 after Christ". Funny. Also why the first day of the new millennium was January 1st 2001, making all the people who partied in 1999-2000 wrong:-)

Actually, nobody was using the Julian calendar (as commonly understood) at the time anyway. Though month length rules were approximately the same as now (in the Roman empire) years were described in a completely different way, typically according to who was currently consul. Scholars of history used numbering, but they counted from the founding of the Rome. Dating according to AD rules was only proposed in the year 525, and took quite a long time to spread. Thus, arguably anyone talking about an AD year bef